Coating composition, a process of producing a coating composition, a coated article, and a method of forming such articles

ABSTRACT

Coating compositions, processes of making coating compositions, coated articles, and methods of forming such articles. Coating compositions include a dispersion of core/shell particles. The core includes a base polymer, and the shell includes a polar polymeric stabilizing agent. One or more hydrophobic particulate fillers is embedded at least partially in the shell. Processes include: (1) selecting the base polymer; (2) selecting the stabilizing agent; (3) selecting the particulate filler(s); (4) melt-blending these, and contacting the melt-blend with water optionally with a neutralizing agent, thereby forming the coating composition including a dispersion. Coated articles include a substrate including cellulose and a dispersion on at least one surface of the substrate. Methods of making coated articles include: (1) providing a substrate including cellulose; (2) providing a coating composition including a dispersion; and (3) applying the coating composition to at least one surface of the substrate, thereby making the coated article.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a non-provisional application claiming priority fromthe U.S. Provisional Patent Application No. 61/122,050, filed on Dec.12, 2008, entitled “COATING COMPOSITION, A PROCESS OF PRODUCING ACOATING COMPOSITION, A COATED ARTICLE, AND A METHOD OF FORMING SUCHARTICLES,” the teachings of which are incorporated by reference herein,as if reproduced in full hereinbelow.

FIELD OF INVENTION

The instant invention relates to a coating composition, a process ofmaking a coating composition, a coated article, and a method of formingsuch articles.

BACKGROUND OF THE INVENTION

The use of polymeric materials as coating compositions as barrierapplications is generally known. Such polymeric coating compositions,for example, may provide a barrier against grease, oil, water and/orvapor. Alternatively, such polymeric coating compositions may provideimproved structural integrity and strength.

Despite the research efforts in developing new coating compositions,there is still a need for a coating composition having improved barrierproperties such as water uptake properties, water vapor transmissionproperties, and oxygen transmission rate properties while maintainingoil and grease resistance properties.

SUMMARY OF THE INVENTION

The instant invention provides a coating composition, a process ofmaking a coating composition, a coated article, and a method of formingsuch articles.

In one embodiment, the instant invention provides a coating compositioncomprising a dispersion comprising: (a) a core comprising a basepolymer; (b) a shell at least partially surrounding said core, whereinsaid shell comprising a polar polymeric stabilizing agent; and (c) oneor more hydrophobic particulate fillers embedded at least partially insaid shell.

In an alternative embodiment, the instant invention further provides aprocess for making a coating composition comprising the steps of: (1)selecting a base polymer; (2) selecting a polar polymeric stabilizingagent; (3) selecting one or more hydrophobic particulate fillers; (4)melt-blending said base polymer, said polar polymeric stabilizing agent,and said one or more hydrophobic particulate fillers; (4) melt kneadingsaid melt-blended base polymer, polar polymeric stabilizing agent andone or more hydrophobic particulate fillers in the presence of water andoptionally in the presence of a neutralizing agent; (5) thereby formingsaid dispersion comprising: (a) a core comprising said base polymer; (b)a shell at least partially surrounding said core, wherein said shellcomprising said polar polymeric stabilizing agent; and (c) said one ormore hydrophobic particulate fillers embedded at least partially in saidshell.

In another alternative embodiment, the instant invention furtherprovides a coated article comprising: a substrate; and a dispersion onat least one surface of said substrate, wherein said dispersioncomprises: (a) a core comprising a base polymer; (b) a shell at leastpartially surrounding said core, wherein said shell comprising a polarpolymeric stabilizing agent; and (c) one or more hydrophobic particulatefillers embedded at least partially in said shell.

In another alternative embodiment, the instant invention furtherprovides a method of making a coated article comprising the steps of:(1) providing a substrate comprising cellulose base material (2)providing a coating composition comprising a dispersion comprising: (a)a core comprising a base polymer; (b) a shell at least partiallysurrounding said core, wherein said shell comprising a polar polymericstabilizing agent; and (c) one or more hydrophobic particulate fillersembedded at least partially in said shell; (3) applying said coatingcomposition to at least one surface of said substrate; and (4) therebymaking said coated article.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the base polymer is athermoplastic polymer selected from the group consisting of an ethylenebased polymer, a propylene based polymer, and combinations thereof.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion comprises 0to 90 percent by weight of the base polymer, based on the total solidweight of the dispersion.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion comprises10 to 50 percent by weight the polar polymeric stabilizing agent, basedon the total solid weight of the dispersion.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the base polymer and polarpolymeric stabilizing agent are the same type of polymeric material,provided each has a different acid number.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the one or morehydrophobic particulate fillers are selected from the group consistingof an inorganic substance, an organic substance, and combinationsthereof.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the inorganic substance isselected from the group consisting of aluminum hydroxide, aragonite,barium sulphate, calcite, calcium sulphate, dolomite, magnesiumhydroxide, magnesium carbonate, magnesite, ground calcium carbonate,precipitated calcium carbonate, titanium dioxide (for example, rutileand/or anatase), satin white, zinc oxide, silica, alumina trihydrate,mica, talc, clay, calcined clay, diatomaceous earth, vaterite, andcombination thereof.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the one or morehydrophobic particulate fillers having a particle size diameter in therange of from 5 nm to 1 μm.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the one or morehydrophobic particulate fillers having a particle size diameter in therange of from 5 nm to 500 nm.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the one or morehydrophobic particulate fillers having a particle size diameter in therange of from 5 nm to 200 nm.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion comprises 1to 50 percent by weight of one or more hydrophobic particulate fillers,based on the total solid weight of the dispersion.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the polar polymericstabilizing agent is selected from the group consisting ofethylene-acrylic acid (EAA), ethylene methyl methacrylate (EMMA),ethylene butyl acrylate (EBA), and combinations thereof.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the polar polymericstabilizing agent is neutralized from 50 to 90 percent.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the polar polymericstabilizing agent is neutralized from 55 to 85 percent.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion has aviscosity in the range of from less than 5,000 cP.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion has aviscosity in the range of from less than 500 cP.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion has aviscosity in the range of from less than 100 cP.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion has aviscosity in the range of from less than 50 cP.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion has a pH inthe range of from 8 to 12.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion has a pH inthe range of from 8.5 to 10.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion has a solidaverage particle size diameter in the range of from 0.2 to 2 μm.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion comprisesfrom 40 to 55 percent by volume of a liquid media, based on the totalvolume of the dispersion.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the liquid media is water.

In an alternative embodiment, the instant invention provides a coatingcomposition, method of producing the same, coated articles madetherefrom, and method of making such coated articles, in accordance withany of the preceding embodiments, except that the dispersion comprisesone or more antifoam agents, one or more wetting agents, one or moreantimicrobial agents, one or more crosslinkers, one or more rheologymodifier agents, one or more auxiliary stabilizing agents, one or moreantiblocking agents, one or more colorants, and one or more additionalfillers; provided, however, that the addition of such additionalcomponents does not negatively impact the coating composition of theinstant invention.

DETAILED DESCRIPTION OF THE INVENTION

The instant invention provides a coating composition, a process ofmaking a coating composition, a coated article, and a method of formingsuch articles.

The coating composition according to the present invention comprises adispersion comprising: (a) a core comprising a base polymer; (b) a shellat least partially surrounding said core, wherein said shell comprisinga polar polymeric stabilizing agent; and (c) one or more hydrophobicparticulate fillers embedded at least partially in said shell. Thedispersion according to the instant invention has a solid averageparticle size diameter in the range of from 0.2 to 2 μm.

Base Polymer

The dispersion of the present invention comprises from 20 to 95 percentby weight of one or more base polymers, based on the total weight of thesolid content of the dispersion. All individual values and subrangesfrom 20 to 95 weight percent are included herein and disclosed herein;for example, the weight percent can be from a lower limit of 20, 25, 30,35, 40, or 45 weight percent to an upper limit of 70, 80, 90, or 95weight percent. For example, the dispersion may comprise from 25 to 95,or in the alternative from 35 to 90, or in the alternative from 45 to 80percent by weight of one or more base polymers, based on the totalweight of the solid content of the dispersion. The dispersion comprisesat least one or more base polymers. The base polymer may, for example,be selected from the group consisting of a thermoplastic material, and athermoset material. The one or more base polymers comprise one or moreolefin based polymers, one or more acrylic based polymers, one or morepolyester based polymers, one or more solid epoxy polymers, one or morethermoplastic polyurethane polymers, one or more styrenic basedpolymers, and combinations thereof.

Examples of thermoplastic materials include, but are not limited to,homopolymers and copolymers (including elastomers) of an alpha-olefinssuch as ethylene, propylene, 1-butene, 3-methyl-1-butene,4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene, 1-hexene, 1-octene,1-decene, and 1-dodecene, as typically represented by polyethylene,polypropylene, poly-1-butene, poly-3-methyl-1-butene,poly-3-methyl-1-pentene, poly-4-methyl-1-pentene, ethylene-propylenecopolymer, ethylene-1-butene copolymer, and propylene-1-butenecopolymer; copolymers (including elastomers) of an alpha-olefin with aconjugated or non-conjugated diene, as typically represented byethylene-butadiene copolymer and ethylene-ethylidene norbornenecopolymer; and polyolefins (including elastomers) such as copolymers oftwo or more alpha-olefins with a conjugated or non-conjugated diene, astypically represented by ethylene-propylene-butadiene copolymer,ethylene-propylene-dicyclopentadiene copolymer,ethylene-propylene-1,5-hexadiene copolymer, andethylene-propylene-ethylidene norbornene copolymer; ethylene-vinylcompound copolymers such as ethylene-vinyl acetate copolymer,ethylene-vinyl alcohol copolymer, ethylene-vinyl chloride copolymer,ethylene acrylic acid or ethylene-(meth)acrylic acid copolymers, andethylene-(meth)acrylate copolymer; styrenic copolymers (includingelastomers) such as polystyrene, ABS, acrylonitrile-styrene copolymer,α-methylstyrene-styrene copolymer, styrene vinyl alcohol, styreneacrylates such as styrene methylacrylate, styrene butyl acrylate,styrene butyl methacrylate, and styrene butadienes and crosslinkedstyrene polymers; and styrene block copolymers (including elastomers)such as styrene-butadiene copolymer and hydrate thereof, andstyrene-isoprene-styrene triblock copolymer; polyvinyl compounds such aspolyvinyl chloride, polyvinylidene chloride, vinyl chloride-vinylidenechloride copolymer, polymethyl acrylate, and polymethyl methacrylate;polyamides such as nylon 6, nylon 6,6, and nylon 12; thermoplasticpolyesters such as polyethylene terephthalate and polybutyleneterephthalate; polycarbonate, polyphenylene oxide, and the like; andglassy hydrocarbon-based resins, including poly-dicyclopentadienepolymers and related polymers (copolymers, terpolymers); saturatedmono-olefins such as vinyl acetate, vinyl propionate, vinyl versatate,and vinyl butyrate and the like; vinyl esters such as esters ofmonocarboxylic acids, including methyl acrylate, ethyl acrylate, n-butylacrylate, isobutyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate,n-octyl acrylate, phenyl acrylate, methyl methacrylate, ethylmethacrylate, and butyl methacrylate and the like; acrylonitrile,methacrylonitrile, acrylamide, mixtures thereof; resins produced by ringopening metathesis and cross metathesis polymerization and the like.These resins may be used either alone or in combinations of two or more.

Examples of suitable (meth)acrylates, as base polymers, include methylacrylate, ethyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexylacrylate, octyl acrylate and isooctyl acrylate, n-decyl acrylate,isodecyl acrylate, tert-butyl acrylate, methyl methacrylate, butylmethacrylate, hexyl methacrylate, isobutyl methacrylate, isopropylmethacrylate as well as 2-hydroxyethyl acrylate and acrylamide. Thepreferred (meth)acrylates are methyl acrylate, ethyl acrylate, butylacrylate, 2-ethylhexyl acrylate, octyl acrylate, isooctyl acrylate,methyl methacrylate and butyl methacrylate. Other suitable monomersinclude lower alkyl acrylates and methacrylates including acrylic andmethacrylic ester monomers: methyl acrylate, ethyl acrylate, n-butylacrylate, t-butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate,isobornyl acrylate, methyl methacrylate, ethyl methacrylate, n-propylmethacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutylmethacrylate, sec-butyl methacrylate, cyclohexyl methacrylate, isodecylmethacrylate, isobornyl methacrylate, t-butylaminoethyl methacrylate,stearyl methacrylate, glycidyl methacrylate, dicyclopentenylmethacrylate, phenyl methacrylate.

In selected embodiments, base polymer comprises a polyolefin selectedfrom the group consisting of ethylene-alpha olefin copolymers, andpropylene-alpha olefin copolymers. In particular, in select embodiments,the base polymer comprises one or more non-polar polyolefins.

In specific embodiments, polyolefins such as polypropylene,polyethylene, copolymers thereof, and blends thereof, as well asethylene-propylene-diene terpolymers, may be used. In some embodiments,preferred olefinic polymers include homogeneous polymers, as describedin U.S. Pat. No. 3,645,992 issued to Elston; high density polyethylene(HDPE), as described in U.S. Pat. No. 4,076,698 issued to Anderson;heterogeneously branched linear low density polyethylene (LLDPE);heterogeneously branched ultra low linear density polyethylene (ULDPE);homogeneously branched, linear ethylene/alpha-olefin copolymers;homogeneously branched, substantially linear ethylene/alpha-olefinpolymers, which can be prepared, for example, by processes disclosed inU.S. Pat. Nos. 5,272,236 and 5,278,272, the disclosures of which areincorporated herein by reference; and high pressure, free radicalpolymerized ethylene polymers and copolymers such as low densitypolyethylene (LDPE) or ethylene vinyl acetate polymers (EVA).

In one embodiment, the base polymer is a propylene-based copolymer orinterpolymer. In some particular embodiments, the propylene/ethylenecopolymer or interpolymer is characterized as having substantiallyisotactic propylene sequences. The term “substantially isotacticpropylene sequences” and similar terms mean that the sequences have anisotactic triad (mm) measured by 13C NMR of greater than about 0.85,preferably greater than about 0.90, more preferably greater than about0.92 and most preferably greater than about 0.93. Isotactic triads arewell-known in the art and are described in, for example, U.S. Pat. No.5,504,172 and WO 00/01745, which refer to the isotactic sequence interms of a triad unit in the copolymer molecular chain determined by 13CNMR spectra. Such propylene based copolymers are further described indetails in the U.S. Pat. Nos. 6,960,635 and 6,525,157, incorporatedherein by reference. Such propylene/alpha-olefin copolymers arecommercially available from The Dow Chemical Company, under thetradename VERSIFY™, or from ExxonMobil Chemical Company, under thetradename VISTAMAXX™.

In other particular embodiments, the base polymer may be ethylene vinylacetate (EVA) based polymers. In other embodiments, the base polymer maybe ethylene-methyl acrylate (EMA) based polymers. In other particularembodiments, the ethylene-alpha olefin copolymer may be ethylene-butene,ethylene-hexene, or ethylene-octene copolymers or interpolymers. Inother particular embodiments, the propylene-alpha olefin copolymer maybe a propylene-ethylene or a propylene-ethylene-butene copolymer orinterpolymer.

In certain embodiments, the base polymer may be a propylene-ethylenecopolymer or interpolymer having an ethylene content between 5 and 20percent by weight and a melt flow rate (230° C. with 2.16 kg weight)from 0.5 to 300 g/10 min. In other embodiments, the propylene-ethylenecopolymer or interpolymer may have an ethylene content between 9 and 12percent by weight and a melt flow rate (230° C. with 2.16 kg weight)from 1 to 100 g/10 min.

In other embodiments, the base polymer may have a crystallinity of lessthan 50 percent. In preferred embodiments, the crystallinity of the basepolymer may be from 5 to 35 percent. In more preferred embodiments, thecrystallinity may range from 7 to 20 percent.

In certain other embodiments, the base polymer is a semi-crystallinepolymer and may have a melting point of less than 110° C. In preferredembodiments, the melting point may be from 25 to 100° C. In morepreferred embodiments, the melting point may be between 40 and 85° C.

In other selected embodiments, olefin block copolymers, for example,ethylene multi-block copolymer, such as those described in the U.S.patent application Ser. No. 11/376,835 may be used as the base polymer.Such olefin block copolymer may be an ethylene/α-olefin interpolymer:

-   -   (a) having a M_(w)/M_(n) from 1.7 to 3.5, at least one melting        point, T_(m), in degrees Celsius, and a density, d, in        grams/cubic centimeter, wherein the numerical values of T_(m)        and d corresponding to the relationship:        T _(m)>−2002.9+4538.5(d)−2422.2(d)²; or    -   (b) having a M_(w)/M_(n) from 1.7 to 3.5, and being        characterized by a heat of fusion, ΔH in J/g, and a delta        quantity, ΔT, in degrees Celsius defined as the temperature        difference between the tallest DSC peak and the tallest CRYSTAF        peak, wherein the numerical values of ΔT and ΔH having the        following relationships:        ΔT>−0.1299(ΔH)+62.81 for ΔH greater than zero and up to 130 J/g,        ΔT≧48° C. for ΔH greater than 130 J/g,

wherein the CRYSTAF peak being determined using at least 5 percent ofthe cumulative polymer, and if less than 5 percent of the polymer havingan identifiable CRYSTAF peak, then the CRYSTAF temperature being 30° C.;or

(c) being characterized by an elastic recovery, Re, in percent at 300percent strain and 1 cycle measured with a compression-molded film ofthe ethylene/α-olefin interpolymer, and having a density, d, ingrams/cubic centimeter, wherein the numerical values of Re and dsatisfying the following relationship when ethylene/α-olefininterpolymer being substantially free of a cross-linked phase:Re>1481−1629(d); or

(d) having a molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction havinga molar comonomer content of at least 5 percent higher than that of acomparable random ethylene interpolymer fraction eluting between thesame temperatures, wherein said comparable random ethylene interpolymerhaving the same comonomer(s) and having a melt index, density, and molarcomonomer content (based on the whole polymer) within 10 percent of thatof the ethylene/α-olefin interpolymer; or

(e) having a storage modulus at 25° C., G′ (25° C.), and a storagemodulus at 100° C., G′ (100° C.), wherein the ratio of G′ (25° C.) to G′(100° C.) being in the range of 1:1 to 9:1.

The ethylene/α-olefin interpolymer may also:

(a) have a molecular fraction which elutes between 40° C. and 130° C.when fractionated using TREF, characterized in that the fraction havinga block index of at least 0.5 and up to about 1 and a molecular weightdistribution, M_(w)/M_(n), greater than about 1.3; or

(b) have an average block index greater than zero and up to about 1.0and a molecular weight distribution, M_(w)/M_(n), greater than about1.3.

In certain embodiments, the base polymer comprises a polar polymer,having a polar group as either a comonomer or grafted monomer. Inexemplary embodiments, the base polymer comprises one or more polarpolyolefins, having a polar group as either a comonomer or graftedmonomer. Exemplary polar polyolefins include, but are not limited to,ethylene-acrylic acid (EAA) and ethylene-methacrylic acid copolymers,such as those available under the trademarks PRIMACOR™, commerciallyavailable from The Dow Chemical Company, NUCREL™, commercially availablefrom E.I. DuPont de Nemours, and ESCOR™, commercially available fromExxonMobil Chemical Company and described in U.S. Pat. Nos. 4,599,392,4,988,781, and 5,938,437, each of which is incorporated herein byreference in its entirety. Other exemplary base polymers include, butare not limited to, ethylene ethyl acrylate (EEA) copolymer, ethylenemethyl methacrylate (EMMA), and ethylene butyl acrylate (EBA).

In one embodiment, the base polymer comprises a polar polyolefinselected from the group consisting of ethylene-acrylic acid (EAA)copolymer, ethylene-methacrylic acid copolymer, and combinationsthereof, and the stabilizing agent comprises a polar polyolefin selectedfrom the group consisting of ethylene-acrylic acid (EAA) copolymer,ethylene-methacrylic acid copolymer, and combinations thereof; provided,however, that base polymer has a lower acid number that the stabilizingagent.

In certain embodiments, the base polymer may, for example, comprise anepoxy resin. Epoxy resin refers to a composition which possesses one ormore vicinal epoxy groups per molecule, that is, at least one 1,2-epoxygroup per molecule. In general, such compound is a saturated orunsaturated aliphatic, cycloaliphatic, aromatic or heterocyclic compoundwhich possesses at least one 1,2-epoxy group. Such compound can besubstituted, if desired, with one or more non-interfering substituents,such as halogen atoms, hydroxy groups, ether radicals, lower alkyls andthe like.

Illustrative epoxies are described in the Handbook of Epoxy Resins by H.E. Lee and K. Neville published in 1967 by McGraw-Hill, New York andU.S. Pat. No. 4,066,628, incorporated herein by reference.

Particularly useful compounds which can be used in the practice of thepresent invention are epoxy resins having the following formula:

wherein n has an average value of 0 or more.

The epoxy resins useful in the present invention may include, forexample, the glycidyl polyethers of polyhydric phenols and polyhydricalcohols. As an illustration of the present invention, examples of knownepoxy resins that may be used in the present invention, include forexample, the diglycidyl ethers of resorcinol, catechol, hydroquinone,bisphenol, bisphenol A, bisphenol AP (1,1-bis(4-hydroxylphenyl)-1-phenylethane), bisphenol F, bisphenol K, tetrabromobisphenol A,phenol-formaldehyde novolac resins, alkyl substitutedphenol-formaldehyde resins, phenol-hydroxybenzaldehyde resins,cresol-hydroxybenzaldehyde resins, dicyclopentadiene-phenol resins,dicyclopentadiene-substituted phenol resins tetramethylbiphenol,tetramethyl-tetrabromobiphenol, tetramethyltribromobiphenol,tetrachlorobisphenol A and any combination thereof.

Examples of diepoxides particularly useful in the present inventioninclude diglycidyl ether of 2,2-bis(4-hydroxyphenyl) propane (generallyreferred to as bisphenol A) and diglycidyl ether of2,2-bis(3,5-dibromo-4-hydroxyphenyl) propane (generally referred to astetrabromobisphenol A). Mixtures of any two or more polyepoxides canalso be used in the practice of the present invention.

Other diepoxides which can be employed in the practice of the presentinvention include the diglycidyl ethers of dihydric phenols, such asthose described in U.S. Pat. Nos. 5,246,751; 5,115,075; 5,089,588;4,480,082 and 4,438,254, all of which are incorporated herein byreference, or the diglycidyl esters of dicarboxylic acids such as thosedescribed in U.S. Pat. No. 5,171,820. Other suitable diepoxides includefor example, aw-diglycidyloxyisopropylidene-bisphenol-based epoxy resins(commercially known as D.E.R.® 300 and 600 series epoxy resins, productsof The Dow Chemical Company, Midland, Mich.).

The epoxy resins which can be employed in the practice of the presentinvention also include epoxy resins prepared either by reaction ofdiglycidyl ethers of dihydric phenols with dihydric phenols or byreaction of dihydric phenols with epichlorohydrin (also known as “taffyresins”).

Exemplary epoxy resins include, for example, the diglycidyl ethers ofbisphenol A; 4,4′-sulfonyldiphenol; 4,4-oxydiphenol;4,4′-dihydroxybenzophenone; resorcinol; hydroquinone;9,9′-bis(4-hydroxyphenyl)fluorene; 4,4′-dihydroxybiphenyl or4,4′-dihydroxy-α-methylstilbene and the diglycidyl esters of thedicarboxylic acids.

Other useful epoxide compounds which can be used in the practice of thepresent invention are cycloaliphatic epoxides. A cycloaliphatic epoxideconsists of a saturated carbon ring having an epoxy oxygen bonded to twovicinal atoms in the carbon ring for example as illustrated by thefollowing general formula:

wherein R is a hydrocarbon group optionally comprising one or moreheteroatoms (such as, without limitation thereto Cl, Br, and S), or anatom or group of atoms forming a stable bond with carbon (such as,without limitation thereto, Si, P and B) and wherein n is greater thanor equal to 1.

The cycloaliphatic epoxide may be a monoepoxide, a diepoxide, apolyepoxide, or a mixture of those. For example, any of thecycloaliphatic epoxide described in U.S. Pat. No. 3,686,359,incorporated herein by reference, may be used in the present invention.As an illustration, the cycloaliphatic epoxides that may be used in thepresent invention include, for example,(3,4-epoxycyclohexyl-methyl)-3,4-epoxy-cyclohexane carboxylate,bis-(3,4-epoxycyclohexyl) adipate, vinylcyclohexene monoxide andmixtures thereof.

In certain embodiments, the base polymer comprises a thermoplasticpolyurethane polymer. Such thermoplastic polyurethane polymers aregenerally know, and further described, for example, in the InternationalPublication No. 2008/057878, incorporated herein by reference to theextent that it describes a thermoplastic polyurethane polymer.

Those having ordinary skill in the art will recognize that the abovelist is a non-comprehensive listing of exemplary base polymers. It willbe appreciated that the scope of the present invention is restricted bythe claims only.

Polymeric Stabilizing Agent

The dispersion may further comprise at least one or more polymericstabilizing agents to promote the formation of a stable dispersion. Thedispersion of the instant invention comprises 10 to 60 percent by weightof one or more polymeric stabilizing agents, based on the total weightof the solid content of the dispersion. All individual values andsubranges from 10 to 60 weight percent are included herein and disclosedherein; for example, the weight percent can be from a lower limit of 10,15, 17, or 20 weight percent to an upper limit of 35, 45, 50, 55, or 60weight percent. For example, the dispersion may comprise from 10 to 55,or in the alternative from 10 to 50, or in the alternative from 15 to45, or in the alternative from 15 to 35, or in the alternative from 20to 45 percent by weight of one or more polymeric stabilizing agents,based on the total weight of the solid content of the dispersion. Incertain embodiments, the polymeric stabilizing agent can be a polarpolymer, having a polar group as either a comonomer or grafted monomer.In exemplary embodiments, the polymeric stabilizing agent comprises oneor more polar polyolefins, having a polar group as either a comonomer orgrafted monomer. Exemplary polymeric stabilizing agents include, but arenot limited to, ethylene-acrylic acid (EAA) and ethylene-methacrylicacid copolymers, such as those available under the trademarks PRIMACOR™,commercially available from The Dow Chemical Company, NUCREL™,commercially available from E.I. DuPont de Nemours, and ESCOR™,commercially available from ExxonMobil Chemical Company and described inU.S. Pat. Nos. 4,599,392, 4,988,781, and 5,938,437, each of which isincorporated herein by reference in its entirety. Other exemplarypolymeric stabilizing agents include, but are not limited to, ethyleneethyl acrylate (EEA) copolymer, ethylene methyl methacrylate (EMMA), andethylene butyl acrylate (EBA). Those having ordinary skill in the artwill recognize that a number of other useful polymers may also be used.

If the polar group of the polymer is acidic or basic in nature, thepolymeric stabilizing agent may be partially or fully neutralized with aneutralizing agent to form the corresponding salt. In certainembodiments, neutralization of the stabilizing agent, such as EAA, maybe from 25 to 200 percent on a molar basis; or in the alternative, itmay be from 50 to 110 percent on a molar basis; or in the alternative,it may be from 50 to 90 percent on a molar basis; or in the alternative,it may be from 50 to 75 percent on a molar basis. For example, for EAA,the neutralizing agent may be a base, such as ammonium hydroxide orpotassium hydroxide. In the alternative, for EAA, the neutralizing agentmay, preferably, be a base, such potassium hydroxide. Other neutralizingagents can include lithium hydroxide or sodium hydroxide, for example.In another alternative, the neutralizing agent may, for example, be anyamine such as monoethanolamine, or 2-amino-2-methyl-1-propanol (AMP).Those having ordinary skill in the art will appreciate that theselection of an appropriate neutralizing agent depends on the specificcomposition formulated, and that such a choice is within the knowledgeof those of ordinary skill in the art. The amount of neutralizing agentnecessary to neutralize the polymeric stabilizing agent may be reducedby using appropriate basic inorganic particles as described hereinabove.

Additional stabilizing agents that may be useful in the practice of thepresent invention include, but are not limited to, anionic surfactants,or a non-ionic surfactants. Examples of anionic surfactants include, butare not limited to, sulfonates, carboxylates, and phosphates. Examplesof non-ionic surfactants include, but are not limited to, blockcopolymers containing ethylene oxide and silicone surfactants.Additional stabilizing agents useful in the practice of the presentinvention can be either external surfactants or internal surfactants.External surfactants are surfactants that do not become chemicallyreacted into the base polymer during dispersion preparation. Examples ofexternal surfactants useful herein include, but are not limited to,salts of dodecyl benzene sulfonic acid and lauryl sulfonic acid salt.Internal surfactants are surfactants that do become chemically reactedinto the base polymer during dispersion preparation. An example of aninternal surfactant useful herein includes 2,2-dimethylol propionic acidand its salts.

Hydrophobic Particulate Filler

The dispersion comprises 1 to 50 percent by weight of one or morehydrophobic particulate fillers, based on the total weight of the solidcontent of the dispersion. All individual values and subranges from 1 to50 weight percent are included herein and disclosed herein; for example,the weight percent can be from a lower limit of 1, 3, 5, 10 weightpercent to an upper limit of 15, 25, 35, 45, or 50 weight percent. Forexample, the dispersion may comprise from 1 to 25, or in the alternativefrom 1 to 35, or in the alternative from 1 to 40, or in the alternativefrom 1 to 45 percent by weight of one or more hydrophobic particulatefillers, based on the total weight of the solid content of thedispersion. Such hydrophobic particulate fillers include, but are notelimited to inorganic particles, organic particles, and combinationsthereof. The hydrophobic particulate fillers may have an averageparticle size diameter in the range of 5 nm to 500 nm. All individualvalues and subranges from 5 nm to 500 nm are included herein anddisclosed herein; for example, the average particle size diameter can befrom a lower limit of 5, 10 20, 30, 40, or 50 nm to an upper limit ofless than 100, 100, 200, 250, 300, 350, 400, 450, or 500 nm. Forexample, hydrophobic particulate fillers may have an average particlesize diameter in the range of 5 nm to 400 nm, or in the alternative, 5nm to 350 nm, or in the alternative 5 nm to 300 nm, or in thealternative 5 nm to 250 nm, or in the alternative 5 nm to 200 nm, or inthe alternative 5 nm to 100 nm, or in the alternative 5 nm to less than100 nm.

The inorganic particles used in the present invention may comprise amixture of different inorganic particles with different properties. Theinorganic particles used in the present invention are preferably basic.Either the inorganic particles can be intrinsically basic oralternatively they may be treated to obtain basic functional groups onthe surface. If it is desired to employ non-basic inorganic particles,then it is preferred to treat the non-basic inorganic particles so thatthey exhibit basic groups on the surface. Examples of such treatmentinclude contacting the inorganic particles with an aqueous solution ofat least one hydrolysable polyvalent metal salt, followed byneutralization. The treatment is preferably carried out before the fattyacid or salt thereof is coated on the inorganic particles. The inorganicparticles used in the present invention include, but are not limited to,at least one or more substances selected from the group consisting ofaluminum hydroxide, aragonite, barium sulphate, calcite, calciumsulphate, dolomite, magnesium hydroxide, magnesium carbonate, magnesite,ground calcium carbonate, precipitated calcium carbonate, titaniumdioxide (for example, rutile and/or anatase), satin white, zinc oxide,silica, alumina trihydrate, mica, talc, clay, calcined clay,diatomaceous earth, and vaterite or any combination thereof. If theparticles are not intrinsically basic they need to be treated by anysuitable method to make them basic. The inorganic particles arepreferably calcium carbonate particles, more preferably precipitatedcalcium carbonate. In the alternative, the hydrophobic particulatefillers may be an inorganic particle selected from the group consistingof calcium carbonate, for example, precipitated calcium carbonate,calcium sulphate, for example, gypsum, barium sulphate, aluminum oxide,alumina trihydrate (ATH), TiO₂, fumed silica, precipitated silica,carbon black, synthetic layered silicates, for example, mica or fluoromica, natural layered silicates, for example, montmorillonite,hectorite, saponite, or vermiculite, nanoclays, for example, natural orsynthetic layered silicates containing modifiers improving intercalationand exfoliation, magnesium hydroxide, magnesium carbonate, zinc borate,and talc.

Exemplary organic particles include, but are not limited to, polystyrenebased pigments (or plastic pigment, for example, styrene, styrenebutadiene copolymer), starch based pigments, and the like.

Fluid Medium

The dispersion further comprises a fluid medium. The fluid medium may beany medium; for example, the fluid medium may be water. The dispersionof the instant invention comprises 40 to 70 percent by volume of fluidmedium, based on the total volume of the dispersion. In particularembodiments, the water content may be in the range of from 25 to 65, orin the alternative from 35 to 65, or in the alternative from 40 to 55percent by volume, or in the alternative from 45 to 55 percent byvolume, based on the total volume of the dispersion. Water content ofthe dispersion may preferably be controlled so that the solids content(base polymer plus stabilizing agent) is between 1 percent to 74 percentby volume. In particular embodiments, the solids range may be between 10percent to 70 percent by volume. In other particular embodiments, thesolids range is between 20 percent to 60 percent by volume. In certainother embodiments, the solids range is between 30 percent to 55 percentby volume.

Fillers for the Coating Composition

The coating composition may further comprise one or more fillers. Suchfillers include, but are not limited to, include conventional fillerssuch as milled glass, calcium carbonate, aluminum trihydrate, talc,antimony trioxide, fly ash, clays (such as bentonite or kaolin clays forexample), or other known fillers.

Additives for the Coating Composition

The coating composition may further include additives. Exemplaryadditives may include, but are not limited to, a wetting agent,surfactants, anti-static agents, antifoam agent, anti block agents,crosslinking agents, wax-dispersion pigments, waxes, neutralizingagents, thickeners, compatibilizers, brighteners, rheology modifiers, abiocides, a fungicides, and other additives known to those skilled inthe art.

Application

The coating composition according to the instant invention may beapplied to a substrate. Exemplary suitable substrates include, but arenot limited to, sheet, non-woven material, woven material, film, foams,and the like. Such substrate may comprise organic based materials,inorganic materials, and combinations thereof. The substrate may, forexample, comprise a cellulose based material, a natural polymeric basedmaterial, a synthetic polymeric based material, a metal based material,a mineral based, and combinations thereof. The substrate may be porous,for example, micro-porous. The coating composition may be applied to thesubstrate via a conventional method for applying a coating composition.Such methods are generally known, and include, but are not limited tospraying, dipping, roll coating, blade coating, curtain coating,printing techniques such as flexography and rotogravure, size press,metered size press, screen coating, rod coating combinations thereof,and the like. The coating composition may be applied to the substrate inany amount. For example, the coating composition may be applied to thesubstrate in an amount to produce a coated substrate having a coatweight, based on the dry weight of the dispersion, in the range of 0.5 gper m² of the substrate to 200 g per m² of the substrate, in the rangeof 0.1 g per m² of the substrate to 500 g per m² of the substrate, inthe range of 0.5 g per m² of the substrate to 100 g per m² of thesubstrate, in the range of 0.5 g per m² of the substrate to 10 g per m²of the substrate. After the substrate is coated with the coatingcomposition, at least a portion of the liquid media may be removed. Thedispersion applied onto a substrate may be dried via any conventionaldrying method. Such conventional drying methods include but, are notlimited to, air drying, convection oven drying, hot air drying,microwave oven drying, and/or infrared oven drying. The dispersionapplied onto a substrate may be dried at any temperature; for example,it may be dried at a temperature in the range of equal or greater thanthe melting point temperature of the base polymer; or in thealternative, it may be dried at a temperature in the range of less thanthe melting point of the base polymer. The dispersion applied onto asubstrate may be dried at a temperature in the range of 60° F. (15.5°C.) to 700° F. (371° C.). All individual values and subranges from 60°F. (15.5° C.) to 700° F. (371° C.) are included herein and disclosedherein; for example, the dispersion applied onto a substrate may bedried at a temperature in the range of 60° F. (15.5° C.) to 500° F.(260° C.), or in the alternative, the dispersion applied onto asubstrate may be dried at a temperature in the range of 60° F. (15.5°C.) to 450° F. (232.2° C.). The temperature of the dispersion appliedonto a substrate may be raised to a temperature in the range of equal orgreater than the melting point temperature of the base polymer for aperiod of less than about 40 minutes. All individual values andsubranges from less than about 40 minutes are included herein anddisclosed herein; for example, the temperature of the dispersion appliedonto a substrate may be raised to a temperature in the range of equal orgreater than the melting point temperature of the base polymer for aperiod of less than about 20 minutes, or in the alternative, thetemperature of the dispersion applied onto a substrate may be raised toa temperature in the range of equal or greater than the melting pointtemperature of the base polymer for a period of less than about 10minutes, or in another alternative, the temperature of the dispersionapplied onto a substrate may be raised to a temperature in the range ofequal or greater than the melting point temperature of the base polymerfor a period in the range of 0.1 to 600 seconds. In another alternative,the temperature of the dispersion applied onto a substrate may be raisedto a temperature in the range of less than the melting point temperatureof the base polymer for a period of less than 40 minutes. All individualvalues and subranges from less than about 40 minutes are included hereinand disclosed herein; for example, the temperature of the dispersionapplied onto a substrate may be raised to a temperature in the range ofless than the melting point temperature of the base polymer for a periodof less than about 20 minutes, or in the alternative, the temperature ofthe dispersion applied onto a substrate may be raised to a temperaturein the range of less than the melting point temperature of the basepolymer for a period of less than about 10 minutes, or in anotheralternative, the temperature of the dispersion applied onto a substratemay be raised to a temperature in the range of less than the meltingpoint temperature of the base polymer for a period in the range of 0.1to 600 seconds.

Drying the dispersion applied onto a substrate at a temperature in therange of equal or greater than the melting point temperature of the basepolymer facilitates the formation of a film having a continuous basepolymer phase with a discrete stabilizing agent phase dispersed thereinthe continuous base polymer phase thereby further improving barrierproperties.

End-Use Applications

The coating compositions according to the present invention may be usedas barrier coatings such as water barrier coatings, vapor barriercoatings, oil and grease barrier coatings, and combinations thereof.Inventive articles according to instant invention include food packagingarticles such as pet food bags, frozen food bags, and the like.

Forming the Dispersion

The dispersion can be formed by any number of methods recognized bythose having skill in the art. In one embodiment, one or more basepolymers, one or more polar polymeric stabilizing agents, and one ormore hydrophobic particulate fillers are melt-kneaded in an extruder inthe presence of water and optionally one or more neutralizing agents,such as ammonia, potassium hydroxide, or a combination of the two toform a dispersion compound. In another embodiment, one or more polarpolymeric stabilizing agents and one or more hydrophobic particulatefillers are compounded, and then the compound is melt-kneaded in anextruder in the presence of one or more base polymers, water, and one ormore neutralizing agents. In some embodiments, the dispersion is firstdiluted to contain 1 to 3 percent by weight water and then,subsequently, further diluted to comprise greater than about 25 percentby weight water.

Any melt-kneading means known in the art may be used. In someembodiments, a kneader, a BANBURY® mixer, single-screw extruder, or amulti-screw extruder, for example, a twin screw extruder, is used. Aprocess for producing the dispersions in accordance with the presentinvention is not particularly limited. For example, an extruder, incertain embodiments a twin screw extruder, is coupled to a back pressureregulator, melt pump, or gear pump. Exemplary embodiments also provide abase reservoir and an initial water reservoir, each of which includes apump. Desired amounts of base and initial water are provided from thebase reservoir and the initial water reservoir, respectively. Anysuitable pump may be used, but in some embodiments a pump that providesa flow of about 150 cc/min at a pressure of 240 bar is used to providethe base and the initial water to the extruder. In other embodiments, aliquid injection pump provides a flow of 300 cc/min at 200 bar or 600cc/min at 133 bar. In some embodiments, the base and initial water arepreheated in a preheater.

One or more base polymers, in the form of pellets, powder, or flakes,may be fed from the feeder to an inlet of the extruder where the resinis melted or compounded. One or more polar polymeric stabilizing agents,and one or more hydrophobic particulate fillers first also may be fedsimultaneously with one or more base polymers into the extruder via thefeeder; or in the alternative, one or more hydrophobic particulatefillers may be compounded into one or more polar polymeric stabilizingagents, and then fed into the extruder via the feeder with one or morebase polymers. In some embodiments, additional polar polymericstabilizing agents may further be metered into the extruder. The resinmelt is then delivered from the mix and convey zone to an emulsificationzone of the extruder where the initial amount of water and base from thewater and base reservoirs are added through an inlet. In someembodiments, additional surfactants may be added additionally orexclusively to the water stream. In some embodiments, the melt blendedmixture is further diluted with additional water inlet from waterreservoir in a dilution and cooling zone of the extruder. Typically, thedispersion is diluted to at least 30 weight percent water in the coolingzone. In addition, the diluted mixture may be diluted any number oftimes until the desired dilution level is achieved. In some embodiments,water is not added into the twin screw extruder but rather to a streamcontaining the resin melt after the melt has exited from the extruder.In this manner, steam pressure build-up in the extruder is eliminated.

EXAMPLES

The following examples illustrate the present invention but are notintended to limit the scope of the invention.

Inventive Dispersions 1-2

The inventive dispersions were made according to the followingprocedure. One or more base polymer resins, one or more polymericstabilizing agent resins, and one or more hydrophobic particulatefillers, as shown in Table I, were selected, and fed into a twin screwextruder simultaneously. Pellets of AFFINITY 8200 and pellets ofPRIMACOR 5980 were physically mixed together in a ratio of 85 partsAFFINITY to 15 parts PRIMACOR 5980 prior to addition to the extruderwith a Schenck Mechatron loss in weight solids feeder. The pressure inthe extruder was maintained at 300 psi throughout the run. Thesecomponents were melt blended in the compounding zone of the extruderthereby forming a melt blended compound. Subsequently, water and basewas metered into the extruder, and the melt blended compound wascontacted with water in the presence of the base. Further water wasmetered into the extruder thereby further diluting the dispersion. Theformulations for inventive dispersions are reported in Table I. Theextrusion conditions are reported in Table II. The inventive dispersionswere tested for their properties, and those properties are listed inTable III. The inventive dispersions were applied to a cellulosic basedsubstrate, that is paper boards supplied from Stora Enso Oyj. having agramage of approximately 240 g/m². The properties of the inventivecoated substrates 1-2 were tested, and reported in Table IV.

The comparative dispersions were made according to the followingprocedure. One or more base polymer resins, and one or more polymericstabilizing agent resins, as shown in Table I, were selected, and fedinto a twin screw extruder simultaneously. These components were andmelt blended in the compounding zone of the extruder thereby forming amelt blended compound. Subsequently, water and base was metered into theextruder, and the melt blended compound was contacted with water in thepresence of the base. Further water is metered into the extruder therebyfurther diluting the dispersion. The formulation components forcomparative dispersions are reported in Table I. The extrusionconditions are shown in Table II. The comparative dispersions weretested for their properties, and those properties are listed in TableIII. The comparative dispersions were applied to cellulosic basedsubstrates, that is paper boards supplied from Stora Enso Oyj. having agrammage of approximately 240 g/m². The properties of the comparativecoated substrates 1-3 were tested, and reported in Table IV.

TABLE I Inventive Inventive Comparative Comparative ComparativeDispersion Dispersion Dispersion Dispersion Dispersion 1 2 1 2 3 Raw — —— — — Material Solid Content [%] Sample 8.6 wt % CaCO₃: 47.9 100 — — — —(AFFINITY 8200/PRIMACOR 5980i Sample 14.6 wt % 51.0 — 100 — — — CaCO₃:(Affinity 8200/Primacor 5980i) POD 8501 [control 2] 47.7 — — 100 100 100(Affinity 8200/Primacor 5980i) Setacarb (post addition 75.0 — — — 9.417.1 of CaCo₃) from Omya Formulation Solid — 40 40 40 40 40 Content [%]pH-value — 10.5 10.5 10.2 10.2 10.2

TABLE II Base Flow Initial Rate Dilution Water Flow (base is 45 PolymerMix CaCO₃ Water Flow Barrel Vmean Rate % wt KOH) Flow Rate Flow RateRate Temp. Screw Particle Size Sample (g/min) (g/min) (g/min) (g/min)(g/min) ° C. RPM (μm) Inventive 12.7 2.9 68.0 7.6 63.2 150 400 0.51Dispersion 1 Inventive 12.7 2.9 60.4 15.2 63.2 150 400 0.66 Dispersion 2Comparative 12.7 3.6 75.6 0 62.5 160 500 0.8 Dispersion 1

TABLE III 3M Kit Rating Test Results Sample Flat Kit Rating NumberInventive 1 12 Inventive 2 12 Comparative 1 12 Comparative 2 12Comparative 3 12

TABLE IV WVTR Cobb WVTR (g/m²/24 hr) OTR Test (g/m²/24 hr) water vapor(cc/m²/day) (g/m²) water vapor transmission Oxygen water transmissionrate rate RH 90%, Transmission Dispersion uptake (RH 50%, 25° C.) 38° C.Rate Inventive 4.4 11.9 288.7 21,460 Dispersion 1 Inventive 3.0 13.7222.7 19,340 Dispersion 2 Comparative 14.5 37.1 670 24,422 Dispersion 1Comparative 16.1 17.4 573.9 31,889 Dispersion 2 Comparative 14.5 19599.3 23,601 Dispersion 3

TEST METHODS

Test methods include the following:

The Cobb water resistance test was measured via Tappi Test Method T 441om-90 under the following conditions for coated paperboards:

-   Test period: 2 minutes-   Sample size: 13 cm²-   Amount of deionized water: 100 ml

The oxygen transmission rate (OTR) measurement was performed bymeasuring oxygen permeability using a measuring apparatus (Model OX-TRANModel 2/21, manufactured by Mocon, Inc.) at a temperature of 23° C. anda relative humidity (RH) of 50 percent. Within this instrument, eachmeasurement unit is composed of two cells, which are separated by thesample. In one cell carrier gas (nitrogen) is routed, where the othercell is flushed with a test gas (oxygen). Both gases have a definedtemperature and relative humidity (RH). After the measurement isstarted, oxygen is allowed to enter the Coulox sensor. This sensor, whenexposed to oxygen, generates an electrical current which is proportionalto the amount of oxygen entered.

The water vapor transmission rate (WVTR) was measured using ASTM E96-80dish test. The test measures the transmission of moisture from a wetchamber through a test specimen (sheet) and into a dry chambercontaining a desiccant.

3M Kit Test

Grease and oil kit testing liquids are made according to formulas shownin Table A. Castor oil (USP Grade 99-100 percent), toluene (ACS Grade,99.5 percent min. by gas chromatography), heptane (Reagent grade, 99.9percent min. with 99.0 percent n-heptane) are purchased from VWRInternational.

TABLE A Composition of Kit Test Liquids Kit # 1 2 3 4 5 6 7 8 9 10 11 12Castor Oil 100 90 80 70 60 50 40 30 20 10 0 0 (g) Toluene 0 5 10 15 2025 30 35 40 45 50 45 (g) Heptane 0 5 10 15 20 25 30 35 40 45 50 55 (g)

The oil and grease resistance “Kit Test” is performed on the samplesaccording to TAPPI UM 557 “Repellency of Paper and Board to Grease, Oil,and Waxes (Kit Test).” The Kit Test is a procedure for testing thedegree of repellency of paper or paperboard having a coating.

The Kit Test is conducted as follows. Obtain five representative samples(5.08 cm×5.08 cm) of each of the coated base papers. Deposit one drop ofthe Kit Rating Number test reagent onto a flat surface of the coatedbase paper having the coating composition of the present disclosure froma height of 2.54 cm. After 15 seconds, wipe away the excess Kit RatingNumber test reagent with a clean tissue or cotton swatch. Immediatelyexamine the surface of the coated base paper.

The coated base paper is assigned a failure if the test surface shows apronounced darkening as compared to an untested coated base paper. If,however, the coated base paper passes, repeat the above described testwith a new sample of coated base paper with the next higher Kit RatingNumber test reagent until a failure Kit Rating Number test reagent isfound. The average of the five highest passing Kit Rating Number testreagent rounded to the nearest 0.5 is reported as the flat Kit RatingNumber for the coating composition on the coated base paper.

The present invention may be embodied in other forms without departingfrom the spirit and the essential attributes thereof, and, accordingly,reference should be made to the appended claims, rather than to theforegoing specification, as indicating the scope of the invention.

We claim:
 1. A process for producing an aqueous coating compositioncomprising the steps of: forming a melt blend of one or more basepolymers, one or more polar polymeric stabilizing agents, and one ormore hydrophobic particulate fillers, wherein the one or more basepolymers are selected from the group consisting of ethylene/acrylic acidcopolymers and ethylene/methacrylic acid copolymers; injecting aninitial amount of water and neutralizing agent into said melt blend;melt kneading said melt blend, optionally in the presence of furtherneutralizing agent, under elevated pressure and heat sufficient toeliminate steam pressure build-up; thereby forming an aqueous dispersionof particles, the particles comprising: a core comprising said basepolymer; a shell at least partially surrounding said core, wherein saidshell comprises said polar polymeric stabilizing agent; and said one ormore hydrophobic particulate fillers embedded at least partially in saidshell, the at least one or more hydrophobic particulate fillers having aparticle size diameter in the range of from 5 nm to 250 nm.
 2. Theprocess for producing an aqueous coating composition of claim 1, whereinthe one or more polar polymeric stabilizing agents comprisesethylene/acrylic acid copolymer.